I have understood that the expenses are subtracted from the current value of a series of equal payments for the 100,000 (since the exercise said that these expenses are due to the cost of maintaining a machine worth 100.000 every year, but increases each year at 30.000 .)

Out of that comes what is before color rectangle in the image, but the other calculation itself does not understand what I am not how they operate with those 30,000 that increase annually on the 100,000 additional maintenance costs of the machine.